A substantial number of liquids must be treated to meet government laws for release into the environment. For example, many aqueous streams typically contain one or more impurities, such as suspended solids, dissolved organic matter, microorganisms, dissolved mineral matter and the like. Another example is in textile dyeing and printing processes. Specifically, in nearly all textile dyeing and printing processes, some fraction of the applied colorant will not bind to the substrate. These unbound dyes and reactants are typically removed by a water rinsing process, generating large quantities of aqueous effluent that must be disposed of in an environmentally acceptable manner. Furthermore, prior to disposing, the waste water (i.e., aqueous effluent) must often also be treated to kill, remove, and/or oxidize bacteria, spores, and other microorganisms.
Previous attempts have disposed of the components in the aqueous effluents by passing the effluents through continuous chemical reactors such as a plug flow reactor containing adsorbent beads or particles having specific surface functionalities, through which dyes and other waste components found in effluents are adsorbed. Specifically, the beads or particles are packed into a column in the plug flow reactor and an aqueous effluent is pumped through the column, thereby exposing the surface of the beads or particles to allow for adsorption of the components in the effluent to occur. These moieties can be adsorbed onto the surface and within the pores of the beads or particles.
One problem with processing aqueous effluent through a column such as that of a conventional plug flow reactor, is that many of the components to be adsorbed (e.g., dyes and reactants) must travel through a hydrodynamic boundary layer surrounding the bead or particle. This boundary layer is a source of resistance for the components, which prolongs the adsorption process and increases time and costs of the removal of unbound components from aqueous effluents.
One previous attempt to reduce adsorption time required to remove the components from aqueous effluents is by increasing flow rate of the processing stream in the plug flow reactor. This reduces the thickness of the hydrodynamic boundary layer, which enhances the rate at which the transport of components to the surface of the beads and particles can occur. This solution, however, results in less residence time in the plug flow reactor for the adsorption process to occur. Additionally, there is increased pressure drop across the reactor, and as such, larger plug flow reactor geometries and processing equipment are required.
Other attempts have utilized ozone-based decontamination. Historically, however, ozone decontamination has not been used for highly concentrated contaminants because it is difficult to get enough ozone into the water and the capital and energy costs are too high. As such, aqueous effluents having highly concentrated contaminants must be disposed of using alternative methods. For example, waste water from making pesticide and herbicide intermediates, which can have a COD (“Chemical Oxygen Demand”) of 10,000 is hauled off and deep well injected as a hazardous waste because the nitrol phenols would otherwise poison the municipal treatment plant. In addition, these high concentration waste fluids are very sudsy. Using a gas, such as ozone, to oxidize the contaminants introduces the problem of stable suds formation pump and consequent cavitation.
Based on the foregoing, there is a need in the art for a treatment system that both prevents a thick hydrodynamic boundary layer from forming, allowing for quicker more efficient removal of components from aqueous effluents, and easily removes even high concentrations of waste components from aqueous effluents.